Biomedical subjects

Michiel P de Looze

Publications and source records attributed to Michiel P de Looze.

5 recordsLinked to original sources

PubMed2006

The effect of joystick handle size and gain at two levels of required precision on performance and physical load on crane operators.

The study was designed to determine the effect of joystick handle size and (display-control) gain at two levels of required task precision on performance and physical load on crane operators. Eight experienced crane operators performed a simulated crane operation task on a computer by use of a joystick with either a short or a large handle. The task was performed at three gain levels and at two levels of required precision. Task performance, wrist and forearm postures, upper extremity muscle activity, perceived exertion and perceived comfort were measured.Task performance improved when using the joystick with the short handle and when working at a higher gain, while physical load decreased or remained the same. An increased level of required task precision was associated with a lower performance, but physical load was not affected. External validity of the simulated crane task seemed sufficient enough to extrapolate the results to practice.A joystick with a short handle is recommended, as this leads to an increased performance whilst the operator's physical load decreases or remains the same. Further optimization of performance and physical load can be achieved by optimizing gain settings of the joystick in relation to the task and type of joystick used.

Adult↗

PubMed2005

Workload of window cleaners using ladders differing in rung separation.

The objective of the present study was to compare energetic workload, perceived exertion, perceived discomfort, safety, and mechanical load at lower limb joints among window cleaners during usage of extension ladders with 30 and 35 cm rung separation. Eleven healthy male professional window cleaners of short and tall stature participated in this study. No significant differences between 30 and 35 cm rung separation were observed for the energetic workload. Results concerning the perceived exertion, discomfort, and safety indicate that 35 cm rung separation is preferred. Based on the mechanical load at the hip, knee, and ankle during ascending and descending the ladder, 30 cm rung separation is preferable to 35 cm rung separation. It is advised to climb ladders with the knees inside the side rails of the ladder, but this seems only possible with 35 cm rung separation. Findings of the presents study suggest that overall, a 35 cm rung separation is marginally favourable while using extension ladders.

Adult↗

PubMed2003

Sitting comfort and discomfort and the relationships with objective measures.

The concepts of comfort and discomfort in sitting are under debate. There is no widely accepted definition, although it is beyond dispute that comfort and discomfort are feelings or emotions that are subjective in nature. Yet, beside several subjective methodologies, several objective methods (e.g. posture analysis, pressure measurements, electromyography (EMG) are in use to assess sitting comfort or discomfort. In the current paper a theoretical framework is presented, in which comfort and discomfort were defined and the hypothetical associations with underlying factors were indicated. Next, the literature was reviewed to determine the relationships between objective measures and subjective ratings of comfort and discomfort. Twenty-one studies were found in which simultaneous measures of an objective parameter and a subjective rating of comfort or discomfort were obtained. Pressure distribution appears to be the objective measure with the most clear association with the subjective ratings. For other variables, regarding spinal profile or muscle activity for instance, the reported associations are less clear and usually not statistically significant.

Equipment Design↗

PubMed2003

The effects of precision demands during a low intensity pinching task on muscle activation and load sharing of the fingers.

High precision demands in manual tasks can be expected to cause more selective use of a part of the muscular synergy involved. To test this expectation, load sharing of the index finger and middle finger was investigated during a pinching task. Myoelectric activation of lower arm and neck-shoulder muscles was measured to see if overall level of effort was affected by precision demands. Ten healthy female subjects performed pinching tasks with three levels of force and three levels of precision demands. The force level did not significantly affect the relative contribution of the index and middle finger to the force. Higher precision demands, however, led to higher contribution of the index finger to the pinch force. Consequently, a more selective load of the forearm and hand occurs during tasks with high precision demands. The variability of the force contribution of the fingers increased during the task. No effects of precision demand on the activation of forearm and neck-shoulder muscles were found. Force level did affect the EMG parameters of several muscles. The effects were most apparent in the muscles responsible for the pinch force, the forearm muscles. Activation of these muscles was higher at higher force levels. In the trapezius muscle at the dominant side EMG amplitudes were lower at the high pinch force compared to the low force and median force conditions.

Adult↗

PubMed2003

Effects of software programs stimulating regular breaks and exercises on work-related neck and upper-limb disorders.

OBJECTIVES: This study evaluated the effects on work-related neck and upper-limb disorders among computer workers stimulated (by a software program) to take regular breaks and perform physical exercises. Possible effects on sick leave and productivity were studied as well. A randomized controlled design was used with cluster randomization. Altogether 268 computer workers with complaints in the neck or an upper limb from 22 office locations were randomized into a control group, one intervention group stimulated to take extra breaks and one intervention group stimulated to perform exercises during the extra breaks during an 8-weekperiod. Questionnaires were administered before andafter the intervention, and questions were generated by the software during the intervention period. Computer usage was recorded online. RESULTS: The data on self-reported recovery suggested a favorable effect; more subjects in the intervention groups than in the control group reported recovery (55% versus 34%) from their complaints and fewer reported deterioration (4% versus 20%). However, a comparison between the reported pre- and postintervention scores on the severity and frequency of the complaints showed no significant differences in the change among the three groups. No effects on sick leave were observed. The subjects in the intervention groups showed higher productivity. CONCLUSIONS: The use of a software program stimulating workers to take regular breaks contributes to perceived recovery from neck or upper-limb complaints. There seems to be no additional effects from performing physical exercises during these breaks.

Analysis of Variance↗